Turn on C++11 when building with gcc4.8+

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index d94cb484d8a6f715332432182a49e929f4078a35..952f7004078e12c658f6335c0091cd55ac1f2a55 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -4136,7 +4136,33 @@
             'ldflags': [
               '-Wl,--disable-new-dtags',
             ],
-          }]
+          }],
+          ['gcc_version>=48', {
+            'target_conditions': [
+              ['_toolset=="target"', {
+                'cflags_cc': [
+                  '-std=gnu++11',
+                  # See comment for -Wno-c++11-narrowing.
+                  '-Wno-narrowing',
+                  # TODO(thakis): Remove, http://crbug.com/263960
+                  '-Wno-literal-suffix',
+                ],
+              }],
+            ],
+          }],
+          ['host_gcc_version>=48', {
+            'target_conditions': [
+              ['_toolset=="host"', {
+                'cflags_cc': [
+                  '-std=gnu++11',
+                  # See comment for -Wno-c++11-narrowing.
+                  '-Wno-narrowing',
+                  # TODO(thakis): Remove, http://crbug.com/263960
+                  '-Wno-literal-suffix',
+                ],
+              }],
+            ],
+          }],
         ],
       },
     }],